The coarser and cruder Donald Trump becomes, and the more ill-informed on the issues he sounds, the more he coasts in the polls. Apparently, a few of his targets must be regarded as unsympathetically as their defamer.

Trump is rightly mocked for cynically spreading quid pro quo money around. But he quickly counters that his critics — from Hillary Clinton to his Republican rivals — have all asked him for such cash or for favors.

Trump preps little. He has no real agenda. And he makes stuff up as he goes along. For such a New York brawler, he has thin skin, smearing his critics, often in creepy fashion. How can a former Democrat, once a pro-choice, pro-amnesty liberal and a supporter of single-payer health care, remain the godhead of the conservative base for weeks on end?

The answer is that Trump is a catharsis for 15 percent to 20 percent of the Republican electorate. They apparently like the broken china shop and appreciate the raging bull who runs amok in it. Politicians and the media are seen as corrupt and hypocritical, and the nihilistic Trump is a surrogate way of letting them take some heat for a change.

Some of Trump”s companies may have declared bankruptcy. But if that is so bad, why is the U.S. government running up $18 trillion in national debt? If Trump ran his businesses the way government manages the Social Security Trust Fund, would we criticize him for running a Ponzi scheme?

We have learned that the supposedly sacrosanct IRS is as conniving as any Third World junta. Is the coarse Donald Trump any more dishonest than the smooth former IRS official Lois Lerner?

Trump is uncouth and reckless in his language. But former Attorney General Eric Holder disparaged Americans as “cowards.” Barack Obama all but called his Republican critics kindred souls to Iranian hardliners. Did Trump make fun of the Special Olympics the way the president once did when referring to his own poor bowling form?

Vice President Joe Biden once used racist language to characterize then-candidate Obama. “You got the first mainstream African-American who is articulate and bright and clean and a nice-looking guy,” Biden said. Trump is crass and in your face, but his supporters see his venom as no worse than that of the foul-mouthed Sen. Harry Reid, who gets a pass from the media.

The grandees of Planned Parenthood talk of their abstract compassion. But in secret videos, they boast of trafficking in human body parts, which is as macabre as anything out of Dickensian London. Do Trump”s wheeler-dealer businesses peddle fetal arms and legs on the side?

Trump”s jujitsu style begs the question of whether many of the objects of his ire are any less reckless than he.

The government and media talk compassionately of amnesty and sanctuary cities. But the repugnant Trump reflects the anger of millions who are tired of hearing only of dreamers, with rare mention that undocumented immigrants commit murder at a rate much higher than the national average, or that more than a quarter of all federal inmates are non-citizens, most of them here illegally.

Did the tragic fate of Kate Steinle — murdered in San Francisco by a frequently deported, frequently paroled undocumented immigrant — prove Trump crazy? Was it an aberration or the logical wage of sanctuary cities?

Mexico published a didactic comic book to advise its own citizens how to illegally cross the border. It rakes in more than $20 billion in annual remittances, saves money on social spending and uses America as a safety valve for its own failures. It is certainly crude of Trump to stereotype Mexico as an enemy of the U.S. But does Mexico not sometimes connive against its northern neighbor?

Without detail, Trump derides President Obama”s Iran pact in buffoonish terms, as if Trump is judging a bad deal on his reality TV show “The Apprentice.”

But is he wrong? If the Iranian theocracy sincerely plans to stop uranium enrichment, dismantle centrifuges, ensure anytime/anywhere inspections and stop exporting terrorism, why, then, are Israel, Egypt, Saudi Arabia and most moderate Middle Eastern nations against the deal, and China and Russia for it?

Trump is a nasty catharsis through which some fed-up conservatives are venting their furor over the plight of the country and politically correct hypocrisy. The mystery among the political and media class is how quickly these disgruntled conservatives will be cleansed and get Trump out of their systems, and whether it will happen before he does other Republican candidates real damage.

For now, it will take a bit more of the unfiltered Trump”s preposterousness and anti-PC bluster before his teed-off fans are finally pacified.

Scorning or ridiculing Trump”s hypocrisies, narcissism or outlandishness won”t silence him, much less win over his supporters. That will happen only when voters find a more savvy, more informed, more polite — but equally blunt and unafraid — version of Trump, perhaps a candidate like either Carly Fiorina, Ted Cruz, Marco Rubio or Scott Walker, all of whom are more likely to channel unapologetic conservative anger rather than crudely amplify it.

Trump will fade when his brand of medicine becomes even worse than the disease. Apparently we are not quite there yet.